net.sandius.rembulan.compiler.gen.asm.StaticConstructorMethod.java Source code

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Here is the source code for net.sandius.rembulan.compiler.gen.asm.StaticConstructorMethod.java

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/*
 * Copyright 2016 Miroslav Jan?ek
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package net.sandius.rembulan.compiler.gen.asm;

import org.objectweb.asm.tree.FieldInsnNode;
import org.objectweb.asm.tree.InsnList;
import org.objectweb.asm.tree.InsnNode;
import org.objectweb.asm.tree.LabelNode;
import org.objectweb.asm.tree.MethodInsnNode;
import org.objectweb.asm.tree.MethodNode;
import org.objectweb.asm.tree.TypeInsnNode;

import java.util.Objects;

import static org.objectweb.asm.Opcodes.ACC_STATIC;
import static org.objectweb.asm.Opcodes.DUP;
import static org.objectweb.asm.Opcodes.INVOKESPECIAL;
import static org.objectweb.asm.Opcodes.NEW;
import static org.objectweb.asm.Opcodes.PUTSTATIC;
import static org.objectweb.asm.Opcodes.RETURN;

class StaticConstructorMethod {

    private final ASMBytecodeEmitter context;
    private final ConstructorMethod ctorMethod;
    private final RunMethod runMethod;

    public StaticConstructorMethod(ASMBytecodeEmitter context, ConstructorMethod ctorMethod, RunMethod runMethod) {
        this.context = Objects.requireNonNull(context);
        this.ctorMethod = Objects.requireNonNull(ctorMethod);
        this.runMethod = Objects.requireNonNull(runMethod);
    }

    public boolean isEmpty() {
        return context.hasUpvalues() && runMethod.constFields().isEmpty();
    }

    public MethodNode methodNode() {

        MethodNode node = new MethodNode(ACC_STATIC, "<clinit>", "()V", null, null);

        InsnList il = node.instructions;

        LabelNode begin = new LabelNode();
        LabelNode end = new LabelNode();

        il.add(begin);

        if (!context.hasUpvalues()) {
            il.add(new TypeInsnNode(NEW, context.thisClassType().getInternalName()));
            il.add(new InsnNode(DUP));

            il.add(new MethodInsnNode(INVOKESPECIAL, context.thisClassType().getInternalName(), "<init>",
                    ctorMethod.methodType().getDescriptor(), false));

            il.add(new FieldInsnNode(PUTSTATIC, context.thisClassType().getInternalName(),
                    context.instanceFieldName(), context.thisClassType().getDescriptor()));
        }

        if (!runMethod.constFields().isEmpty()) {
            for (RunMethod.ConstFieldInstance cfi : runMethod.constFields()) {
                il.add(cfi.instantiateInsns());
            }
        }

        il.add(new InsnNode(RETURN));
        il.add(end);

        return node;
    }

}